Objective: Avoid helicopter fire.
Find the grate on the left side. Shoot open the grate and crawl through the vent shaft. Exit through the grate at the end. The enemy helicopters lies through the windows on the left. Enemies populate the path ahead toward the large stairwell (grab the health underneath if needed). Keep an eye on the helicopter and avoid its machine gun and rocket fire. As you move up the stairs, beware of the sniper to the right.
At the top of the stairs, cross the planks carefully and avoid the helicopters barrage from your right. Move through the tight corridor. The next stairwell contains an RPG launcher and a sniper above. Plus there are additional enemies at the bottom of the stairs and one in an alcove to the left (conveniently its also a good temporary hiding spot and contains a health pack). This is a great area for a flashbang. Toss one around the corner to disorient the RPG launcher (at minimum) so you can mop up the remaining troops. Beware of snipers above and behind you. Oh, and by the way, for fun jump out of the building to read the mission failure message--but save your game first!
Cross the wooden planks to the far side. Before entering the hall on the right, search the end of this floor for a medkit. Check just beyond the medkit on the right for a distant ledge. Leap to this ledge and find a heavy machine gun and ammunition. Leap from here to the top of the staircase below (just to the left) and retrace your steps back up to the previous floor. Enter the door on the right and eliminate the enemies inside.
Enter the door on the right. Watch out for the radicals at the top of the staircase on the right and another guard behind a door ahead. Enter that room ahead for plentiful ammo and some health and armor. Go up the stairs. Move across the rooftop (defeating enemies, including snipers above you) as you move. Continue through a short tunnel to another section of the roof. Helicopters hover around your position.
Walk along a ledge running to the right. Avoid the helicopter fire as you move. Find a small room on the right; it contains enemies but also ammo, health, and armor. Resume course across the ledge. At the end, turn to the right and shoot the RPG launcher.
Enter the area and immediately turn to the right and eliminate the two radicals posted here. A grenade would also do the job nicely. Move to that position and turn around and eliminate the other guards in the area. Cross this portion of the roof to the right side and find the switch box. Pull the lever. Look through the fence above and shoot the guards.
Move out onto the helipad. The allied helicopter has been shot down. Gather the health and ammo and eliminate the radicals on the pad and a sniper on a balcony. You can also see the leader through bulletproof glass; he has the nuke detonator.
A door opens adjacent to the helipad. Eliminate the enemy that arrives and shoot the RPG launcher at the far end. Use the medkit if needed. Climb the ladder. Weave through the narrow space. Blast an enemy around a left corner. Grab the ammo and health nearby. Move toward the radio tower and shoot the radicals in the distance.
Move beyond the radio tower and face more guards taking cover ahead. Additional guards (including some far in the distance) wait around the corner to the left. The sniper rifle from the security station proves especially valuable here. Eliminate all enemies (grab the health pack if needed) and press onward. Go up the staircase at the far end. Open the double doors on the right. Use the medkit if needed. Start moving to the left. You black out! You wake up in the radical leaders custody.
Objective: Fight the terrorist leader.
Grab the knife to your left. Hit him quickly with the knife. Use quick strikes and youll be too fast for him to retaliate. He escapes up the overhead ladder. A door on the left opens and a guard emerges. Quickly knife him and enter the room. Use the medkit and grab the weapon and ammo in the corner. Beware of the group of radicals to the right side.
Objective: Defuse bombs on communication equipment.
Watch for the radicals in the corners. Find the first bomb on the far right side. Defuse it by standing adjacent to the bomb and pressing the "use" key. Once the first one has been defused, return to the first piece of communication equipment on the left. Defuse the second bomb. A door opens at the opposite end of the room. A group of radicals protect the nuke. Kill them quickly then defuse the nuclear device. Grab the health from the room and exit. Watch for the open doors to the left. A couple of heavy machine gunners enter. Defeat them.
Objective: Eliminate terrorist leader before he can remote detonate nuke.
Quickly move to the right and grab the radio-controlled bomb. Return to the left and spot the terrorist leader in an upper room. Place the RC bomb on the pillar and move away. Detonate and watch him plummet to his death Hans Gruber-style.